There number of options

1) if your printer is netword ready, basically saying your printer has network driver, you can just plug your printer to a port on router; if your printer supports wireless, you can use wireless network too.

2) if you printer does not have network driver, you can use a router which has a printer port - this is saying your router has a built-in printer server (also called print server).  Just plug your printer to the printer port.

3) if your router does not have a printer port, you would need to buy a printer server, plug it into a port on router, then you plug your printer to printer server.

4) if non of above, you can connect your printer to one of your pcs, other pcs can print through network but you will need (a) to share documents between pcs; (b) this particular pc has to be on when you need to print a file from another pc.

5) last resort - plug your printer to the pc/laptop directly which has the file you want to print from.